Field of the Invention
The present invention relates to an imaging apparatus and particularly relates to an imaging apparatus capable of acquiring a depth map.
Description of the Related Art
As conventional approaches to acquire a depth map simultaneously with an image for viewing, there are a stereo approach (e.g., Patent Literature 1), depth from defocus (DFD) (Patent Literature 2), depth from focus (DFF) (Patent Literature 3), and the like. These approaches are passive approaches that do not require special lighting and therefore are suitable for a general imaging apparatus. DFD and DFF are methods in which, based on blurs in shot images being different depending on the depth to a photo scene from an imaging apparatus, the difference in blur of a group of images (two or more images) shot under a plurality of shooting conditions are analyzed to calculate a depth map. The stereo method, on the other hand, is based on the principle of triangulation and calculates a depth map of a target scene on the basis of parallax acquired from the correspondence relationship of respective pixels within shot images of two or more viewing points. Embodiments of the stereo method take various forms such as arranging a plurality of imaging apparatuses or dividing a pupil of an optical system to acquire images of two viewing points with one imaging apparatus.
A depth map calculated in this manner can be applied to various image processing for use in a clip function of clipping out a main subject area or for use in a background blur function of blurring a region other than a main object to artificially narrow the depth of field.    Patent Literature 1: Japanese Patent Application Laid-open No. H04-138577    Patent Literature 2: Japanese Patent Application Laid-open No. H01-167610    Patent Literature 3: International Publication No. WO 2002/082805